This invention relates in general to flexible assembly devices comprising a flexible belt supported by a flexible seamless carrier support sleeve and methods of using the assembly devices.
Coated flexible belts or tubes are commonly utilized for numerous purposes such as electrostatographic imaging members, conveyor belts, drive belts, intermediate image transfer belts, sheet transport belts, document handling belts, and the like.
Flexible electrostatographic imaging members, e.g. belts, are well known in the art. Typical electrostatographic flexible imaging members include, for example, photoreceptors for electrophotographic imaging systems, and electroreceptors or ionographic imaging members for electrographic imaging systems. Both electrophotographic and ionographic imaging members are commonly utilized in a belt configuration. These electrostatographic imaging member belts may be seamless or seamed. For electrophotographic applications, the imaging members preferably have a belt configuration. These belts often comprise a flexible substrate coated with one or more layers of photoconductive material. The substrates are usually organic materials such as a film forming polymer. The photoconductive coatings applied to these substrates may be inorganic such as selenium or selenium alloys or organic. The organic photoconductive layers may comprise, for example, single binder layers in which photoconductive particles are dispersed in a film forming binder or multilayers comprising, for example, a charge generating layer and a charge transport layer.
Electrophotographic imaging members having a belt configuration are normally entrained around and supported by at least two belt rollers in an electrophotographic imaging machine. Generally, one of the rollers is driven by a motor to transport the belt around the rollers during electrophotographic imaging cycles. Since electrophotographic imaging belts, particularly welded seam belts, are not perfectly cylindrical and, more specifically, tend to be slightly cone shaped, these flexible belts tend to "walk" axially along the support rollers. Belt walking causes one edge of the belt to strike one or more edge guides positioned adjacent the ends of the rollers to limit axial movement. Friction between the edge guide and the edge of the imaging belt can cause the belt to wear, rip, buckle, delaminate and otherwise damage the belt.
Imaging belts driven around supporting rollers can slip relative to the surface of the roller during stop and go operations. Belt slipping has been a serious problem when the surface contact friction between the backside of the imaging belt and the elastomeric outer surface of the drive roll is substantially reduced as a result of aging of the elastomeric material or deposition and accumulation of undesirable foreign material on the surface of the drive roll. This slippage can adversely affect registration of images, particularly where multiple, sequentially formed and transferred images must be precisely registered with each other in demanding applications such as color imaging process. Further, when welded imaging belt seams encounter slippage, sophisticated detection systems are required to ensure that images are not formed on the seam when the position of the seam shifts due to slippage. Also, there are other serious drawbacks in terms of belt tracking and problems with good image registration. Welded imaging belts, because of the difficulties associated with perfectly aligning overlapping ends during seam welding, are not as concentric as desired.
Often, the supporting rollers for an electrophotographic imaging belt have a tendency to accumulate dirt or particulates on their surfaces to cause localized particle protrusions and form stress concentration spots in the imaging belt, thereby exacerbating the development of premature mechanical failure. Constant flexing of the belt around these support rollers during machine function can result in imaging belt surface cracking. Cracking of the outer imaging layer leads to copy print defects.
Moreover, the region of a belt located between supporting rollers can vibrate and undesirably alter the often critical distances between the belt imaging surface and devices such as optical exposure means, charging corotrons, development applicators, transfer stations and the like.
In addition, the anti-curl back coating on an imaging belt tends to wear during machine cycling and such wear reduces the effectiveness of the anti-curl back coating from preventing curling of the edges of the belt. Curling of the belt also adversely affects the critical distances between the belt imaging surface and adjacent processing stations.
Attempts to prepare electrostatographic imaging belts using a thick supporting substrate to provide satisfactory beam rigidity and eliminate the need of an anti-curl back coating have been seen to accelerate the onset of dynamic fatigue outer imaging layer cracking, since the added imaging member thickness increases its bending stress when flexed over the machine belt module rollers.
When cycled in a machine, an imaging belt is constantly subjected to an applied 1 lb/in (178.6 gms/cm) belt tension. Belt creep, as a function of time in service and the applied tension, is very undesirable because it promotes imaging belt cracking and shortens its service life.